Instrument Timing Using Synchronized Clocks

1. An instrumentation system, comprising: means for asserting an event trigger signal on an event signal path; a set of instruments each coupled to the event signal path and each having a synchronized clock and an event buffer and means for periodically logging a measurement and a corresponding time-stamp obtained from the synchronized clock into the event buffer, each instrument having a mechanism for freezing the periodic logging in response to the event trigger signal.

2. The instrumentation system of claim 1 , further comprising means for transferring an event time-stamp associated with the event trigger signal to the instruments via a communication network such that the event-time stamp enables correlation among the measurements contained in the event buffers.

3. The instrumentation system of claim 2 , further comprising a timing signal path coupled to each instrument for exchanging timing signals for the synchronized clocks.

4. The instrumentation system of claim 3 , wherein the instruments exchange a time-stamp for each timing signal via the communication network.

5. The instrumentation system of claim 4 , wherein each instrument includes means for adjusting the corresponding synchronized clock in response to the timing signals on the timing signal path and the time-stamps carried on the communication network.

6. The instrumentation system of claim 1 , wherein the event buffers are circular buffers.

7. The instrumentation system of claim 1 , wherein each instrument logs measurements according to a corresponding predetermined sample interval which is derived from the corresponding synchronized clock.

8. An instrument, comprising: synchronized clock; event buffer; means for periodically logging a measurement and a corresponding time-stamp obtained from the synchronized clock into the event buffer; means for freezing the periodic logging in response to an event trigger signal.

9. The instrument of claim 8 , further comprising means for receiving an event time-stamp associated with the event trigger signal via a communication network such that the event-time stamp enables correlation among the measurements contained in the event buffer.

10. The instrument of claim 8 , further comprising means for exchanging a timing signal via a timing signal path for adjusting the synchronized clock.

11. The instrument of claim 10 , further comprising means for exchanging a time-stamp for the timing signal via a communication network.

12. The instrument of claim 11 , further comprising means for adjusting the synchronized clock in response to the timing signal on the timing signal path and the time-stamp carried on the communication network.

13. The instrument of claim 8 , wherein the event buffers are circular buffers.

14. The instrument of claim 8 , further comprising means for deriving a sample interval from the synchronized clock such that the measurements are logged in response to the sample interval.

15. A method for obtaining measurements, comprising the steps of: providing each of a set of instruments with a synchronized clock and an event buffer; periodically logging a measurement and a corresponding time-stamp obtained from the synchronized clocks into the event buffers; asserting an event trigger signal on an event signal path; freezing the periodic loggings in response to the event trigger signal.

16. The method of claim 15 , further comprising the step of transferring an event time-stamp associated with the event trigger signal to the instruments via a communication network such that the event-time stamp enables correlation among the measurements contained in the event buffers.

17. The method of claim 16 , further comprising the step of exchanging timing signals for the synchronized clocks via a timing signal path to the instruments.

18. The method of claim 17 , further comprising the step exchanging a time-stamp for each timing signal via communication network.

19. The method of claim 18 , further comprising the step of adjusting the synchronized clock in response to the timing signals on the timing signal path and the time-stamps carried on the communication network.

20. The method of claim 15 , further comprising the step of deriving a sample interval from the synchronized clock such that the sample interval is used to periodically log the measurements.